Placodus

Say it: PLAK-oh-dus

Name means: “plate tooth”1

Ate: MeatOther sea reptilesEarly Triassic to Late TriassicNot technically a dinosaur

Placodus was a marine reptile that lived about 240 million years ago, during the Middle Triassic. It had a stocky body, a long tail, and a heavy skull with flat teeth for crushing shellfish. It swam in shallow seas and probably spent most of its time on the seafloor looking for food.1

Fun fact: this sea reptile swam while dinosaurs walked on land. Everyone calls them dinos, but they were a different branch of reptiles.

Lived

251 to 227 million years ago2

Early Triassic to Late Triassic

Fossils found in

Central Europe (Germany, France, Poland) and China1 2

Food

Meat1

Length

2.5 to 3 m1

Artist's life restoration of Placodus — How Placodus may have looked, by Nobu Tamura (http://spinops.blogspot.com). CC BY 3.0, via Wikimedia Commons. Scientists still argue about colours and details.

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

cool stuff

Fun facts

Placodus had a rigid body because the bones in its spine were dovetailed together, making its trunk stiff.1

Its belly was covered with special armor made of bent, right-angled abdominal ribs, and it had a row of bony knobs above its backbone.1

Placodus was negatively buoyant, meaning it was heavy and could easily stay on the seafloor without floating up.1

Before scientists knew what Placodus looked like, its teeth were mistaken for fish teeth.1

Placodus was slow and clumsy on land because of its heavy body armor, so it probably only came ashore to lay eggs.1

Its short legs probably ended in webbed feet, and it used its flattened tail to push through the water.1

For dino experts

Scientific name: Placodus
Named by: Agassiz 18332
Group: Other sea reptiles
Family / clade: Placodontidae2
Classification: Placodontia > Sauropterygia2
Age of the rocks: 251 to 227 million years ()2
Rock formations: Jena, Wellenkalk, Vossenveld2
Countries: Germany, Israel, Poland, Netherlands, Italy, China2
Fossil records: 34 in the Paleobiology Database2
Also known as: Anomosaurus, Crurosaurus (older names now counted as the same animal)2
Discovery: Placodus was named by the Swiss naturalist Louis Agassiz in 1833. He originally thought the fossils were fish teeth.1 2

Where the facts come from

Placodus (en.wikipedia.org)
Placodus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

Every fact on this page has a number that points to its source. If we got something wrong, sorry, we are dino fans, not a science journal. Tell us at [email protected] and we will fix it.